Flash lamp



Aug. 10, 1965 w. CRESSMAN FLASH LAM? Filed Oct. 5, 1962 UUUUUUUUU UUUUUUUUU UUULUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU UUUUUUUUU "TULEILJLSLB a* zi [8 20 Inven tor: Geor e W. (313 5 bg c His A torneg United States Parenr D Paented Aug. lil 21955 idite Bftl FLASH LAA.- W. Cressman, Chng e al Electric Company, a corporn v .Filed Oct., 5 1952, ser, i ou il Claim. (Ci. oi -.ul

This invention relates in general to fiash lamps of the type comprising a sealed radiation transmitting envelope containing a quantitv of com'busti'ole light producing material in a comlustion supporting medium, such as an oxygenous gas which enters into a reaction With the com bustible material with the resulting emission of an instantaneous fiash of actinic light of high intensity. More particular-lv, this invention relates to a flash lamp which generates light for a duration of time on the order of several seconds.

In hotography, the need exists for a self contained light source such as a a sh larnp which produces light over a time intcrval snfiicient to pernit time exposures or an extended sequence of pictures. lt is therefore an Object of this invention to provide an improved flash lamp 'having a self contained quantity of light giving combustihle material in which the rate of combustion is controlled so that the light output eXtends over an extended time interval in the range of several seconds.

Moreover, the average movie picture taker photographs sequences of approxim-ately 7 to 10 seconds duration. Therefore another object of this invention is to provide a fiash lamp which emits ligh't of suificient duration to permit such a sequence to be taken. This duration of light emission must be at a sufiiciently 'high level to provide the taking of movies with the presently available film. Therefore, it is another Object of this invention to provide a movie flush *lamp which provides a continuous emission of at least 10,000 lunens for a time period on the order of from 7 to 10 seconds.

In accordance with the above-mentioned objects, the preferred embodiments of the invention provides a movie flash lamp which comprises a sealed envelope containing means for emitting at least 10,000 lumens for a time interval on the order of 7 to 10 seconds, said means includng a combustible Sheet consisting essentially of magnesium having combustion-regulating tabs extending therefrorn disposed in a combustion-supporting mixture of approximately 33% argon and 67% oxygen and means for igniting the 'said combustible Sheet.

In the drawing, FIG. l shows a flesh cordance 'with this inventiou,

FIG. 2 is `a side elevation of -part of the mount, and

FIG. 3 is a section view of the mount taken 'along line 3-3 of FIG. l.

As shown in FIG. l, the ilash lans p comprises a glass envelope 3 having seeured thereto by cement 4- a screwtype base 5. The envelope 3 has fused thereto a glass stern 6 enclosing a :pair of .lead-in wires 7. The lead-in wires *7 support at their upper ends a filament 9 preferally consisting of a short length of fine tungsten wire `hsviug a dianie'ter of the order of 0.7 mil. The inne-r ends of leads 7 are provided with primer beads lil of 'a suitnble fulrninating material. The lead-in wir-:s are provided with inner end portions '211 bent at an angle to the major portion of the 'lead-in wires 7 so that the inner ends :ili lie substantially `transverse to the 'longitudinal axis of the envelope. Externally of envelope 3 the lead-in wires 7 are connected to an end eyelet 12 and side contact 23 of the base The fulminating material in may he of the general type disclosed and claimed in US. Patent 2,230,598- G. H. Merid th, issued April 21, 1942, and conprising an admixture of fine (ie, of the order of 325 sh or ALV larnp made in acfiner) No. 3 grade rnagnesium-irconium and potassium perchlorate pow ders bonded together with `a suitable binder such as `a 2 to 5% solution of nitrocellulose in amyl acetate. For best results, however, :and particularly where the ignition filament 9 is of the diameter of the order of mil, it is preferred that the relative proportion of the above-named powder ingredients be within the particular rarges disclosed and clairned in US. Pa-tent 2,756,577-RM. Anderson, issued July 3i, 1956, such ranges being of the order of some 60 to 90% zirconiurn, 1 to 8% magnesium `and 9 to 35% potassum perchlora te.

To Strengthen the envelope 3 and render it substantally shatter-proof on charge ilashing a protective lacquer coating .of the type disclosed and claimed in US. Patent 2,791,113-1-1. M. Anderson, issned May 7, -1957 is applied to the outer side of the envelcpe, the inner side of the envelope being left hare. However, the racq uer coating ;may 'ne applied to the inner side of the cnve'lope.

An upper extension 17 of stern 6 carries a support rod la? which, in turn, support-s a con-bustible Sheet 19 by means of a clip ze cla ped along its length to Sheet 19 and rod 13 (FIG. 3). Support rod 18 comprises a lower portion 21 extendlng verti-cally out of stem extension 17. The rod 13 is bent at right angles to `lower end portion 21 to provide a horizontal otiset 22 :and again bent at a right angie to provide another ve tica-l portion 2.3 which is clamped within clip 29. It will 'be noted that the r od ili? is made up of a Wire which doubled back on itself with both ends thereof embedded in eXte-nsion *17.

The conhustible `Sheet li consists essentially of magnesium With 2.5 to 3.5% aluminurn, 0.2% manganese, .7% :to 1.3% Zinc, and @76% -silicon, Copper, nicl el, irc-n and other impurities. This material is used because it vaporizes more readily than, for example, aluminum or zirconiun, at the igniticn temperature (approximately 920 K). The combustible Sheet is approximately 1 inch by 3 inch by S mil. Vertical portion 23 of the support rod 18 prevents this relatively large mass of fiexihle material from c ontacting the envelope -wall eliminating any danger of shattering the glass envel-ope.

It has been found that the combustible sheet 19 must be provided and maintained in a relatively planar shape so as to ernit a rnaxirnum amount of light. When the combustihle material is provided in a Curved or curled shape it is believed that the unconsuned material ahsorhs some of the energy and lower light intensities are delivered. Also, the curled or Curved shapes burn irregularly and a long duration of relatively constant light output cannot be niointained. Hencc, to further prevent curling of the Sheet it is consumed, cornbustion-regulang tabs are provided. As shown in 2, tabs 25 are punched in spaced apart rows throughout the surface area of Sheet 19 n alternate rows extending from opposite sides of the Sheet so as to give structural rigidity to it. E'Vhen the Sheet 19 is ignited, the tabs 25' are more readily combustible than the body of the sheet and hence, curling is prevented since the combnstion proceeds regularly on both sides of the Sheet.

The support rod ES is a stainless steel alloy having a co-efiicie t of thermal expansion which closely matches the coeiiicient of expansion of the glass stem e such that when 'the magnesium Sheet 1') is burned, the stem s and rod ES do not expand difterentially so as to c'acl the glass and allow the Sheet to fall onto the envelope wall. The oiset 22 is provided so that the sheet 19 will be supported substantially centrally within envelope 3. Thus, even if the Sheet were to curl as it burns, no contact will be made with the envelope.

The clip 20 consists essentially of alurninum and prevents the unconsuned portion of the combustible she-e from telling against the glass envelope 3 by acting as a .U heat sink. That is, the sheet 19, as it is being consumed, might have a tendency to burn along the junction line between the clip 28 and sheet 19 thus severing unconsumed material from the support. Because the aluminum does not ignite near the temperature of magnesium, the aluminum clip za remains intact and coois that portion of the Sheet 19 closely adjoining clip 2.9' preventing early combustion of that portion.

The lower edge of sheet 19 is supported by clip za in close proximity to filarnent 9 and primer beads HB, the lower edge being provided with serrations 24 so that sheet 19 may be readily ignited. The serrations 24 are made even more readily ignitable by coating them with primer material of approximately the same Composition as printer beads w.

, The envelope 3 is filled with a combustion-supporting gas, the major portion of which is oxygen. However, to "further control the burning of Sheet 19 a gas which does not ente' into the actinic reaction is also provided. While,

theoretically, many gases Would full this function, argon or krypton is considered vastiy superior to that of nitrogen, helium, or Sulfur dioxide. Argon gas is preferred because it would appear that a miXture of approximately 33% argon and 67% oxygen will support combustion for a time period limited only by the amount of oxygen and combustible material present to react. This is believed to be so because the argon seems to be dierentially -attracted -to the metal Sheet present in the envelope and forms a barrier layer between the metal and the oxygen. This layer is effectively stripped away as the material is consumed and only then is more metallic material exposed to oxygen. 7

Although a preferred embodiment of my invention has been disclosedgit Will be understood that the invention is not limited to this specific instruction and arrangement 'of parts shown but may be widely modified within the Spirit and scope of my invention as defined by the appended Claim.

What I claim as new and desire to secure by Letters Patent of the United States is:

A flash lamp comprising a sealed light-transmitting envelope containing combustible means for emitting at least 10,000 lumens for at least 7 seconds including a relatively planar rectangular combustible sheet consisting essentially of magnesium; said Sheet having primer-coated serrations at one edge and combustion-regulating tabs thereon spaced in a regular pattern throughout the surface area of the Sheet; means for supporting said sheet in a longitudinalposition within the envelope including a stem fused to the envelope, a stainless steel Wire mounted in the stem and beat sink means fastened to said Sheet and said Wire thereby securing them together; said heat sink comprising an aluminum clip, a combustion-supporting gaseous mixture within said envelope consisting esssentially of 67% oxygen and 33% of one of the class consisting of argon and krypton and means for igniting said combustible means.

lieterences Cited by the Examiner UNTED STATES PATENTS 1,776,637 9/30 Ostermeier 67-31 1,995,938 3/35 Nichols 67-31 1,996,621 4/35 Kurlander 67-31 2,013,371 9/35 ,Van Leimpt et al 67-31 2,057,583 19/36 Mey 67--31 2,136,234 11/33 Cartun 67-,--31 2,201,294 5 40 Kreidler 67-31 2,238,780 4/41 Reiter et al -4 67-31 2,272,779 2/42 Sarbey 67-31 2,291,983 8/42 Pipkin 67-31 v 2,611,255 9/52 `Pcelma et al 67-31 2,955,44-7 10/60 Fink et al. 67-31 V 3,002,367 10/61 Fink 67-31 EDWARD J. MCHAEL, Primary Examiner. FREDERICK L. MATTESON, JR., Examner. 

